Sea to Summit Trek -1 Down Sleeping Bag

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The Trek -1 Down Sleeping Bag brings the comfort of a spacious tapered-rectangular mummy shape and the versatility of a dual-zip ventilation system to wherever your travels may take you. It combines ULTRA-DRY 650+ loft duck down for water resistance with a 20D recycled polyester shell and lining for durability and comfort and compresses down in the included compression sack for easy packing. The Free Flow Zip System allows multiple configurations including opening it out completely for use as a quilt.


  • Semi-rectangular fit: Spacious and generous, a roomy fit to give you room to move inside the bag, regardless of your sleeping position
  • Sustainable construction with 100% recycled bluesign®-approved 20D polyester shell and lining, a PFC-free water-repellent coating and RDS down
  • 650+ Fill Power, RDS-certified, 85% Down Cluster Premium Duck Down with ULTRA-DRY Down treatment for improved water resistance in damp conditions
  • Free Flow Zip System for reliable, snag-free operation, to provide superior ventilation and allow the bag to be used as a comforter/quilt:
    • Primary zip: full-length #5 zip with zip-plow and two sliders
    • Secondary zip: half-length #5 zip with zip-plow and two sliders
    • Foot box zip: #5 with two sliders
    • Vertical chest baffles, horizontal baffles lower half and base, box wall baffle construction throughout
    • Shaped hood and oversized zip draft tubes to seal in warmth and keep cold out
    • Fitted front draft collar: scalloped over the neck and oversized at the shoulders
    • Internal pocket for phone / GPS / valuables
    • QuiltLock System allows Sea to Summit quilts to be locked into place over the top of the Trek, giving you modular and versatile sleeping bag
    • Form a snug double sleeping bag by zipping to any women's Sea to Summit sleeping bags
    • Includes lightweight Ultra-Sil compression bag and storage cell


Fits to 185cm (Regular), 198cm (Long)
Shoulder Width 79cm (Regular), 84cm (Long)
Foot Width 65.5cm (Regular), 71.5cm (Long)
Compression 13 Litres (both sizes)
Fill ULTRA-DRY Duck Down 650+ Loft, RDS certified
Fill Weight 380g (Regular), 437g (Long)
Average Weight 1119g (Regular), 1253g (Long)
Outer Material 20D recycled polyester
Inner Material 20D recycled polyester with a non-PFC DWR finish
Temperature Rating 3°C comfort rating woman / minus 1°C Lower comfort rating for men; Temperature rated in accordance with ISO 23537-1:2022

ULTRA-DRY Down™: With the introduction of water-repellent ULTRA-DRY Down™ Seat to Summit have virtually eliminated the negative effects moisture has on down. The ULTRA-DRY Down™ water-repellent treatment protects the down from external moisture and condensation from inside the bag. It is a permanent (no loss of treatment effect has been seen in over 14 wash cycles) Nano-level water repellent polymer treatment applied to Sea to Summit high loft, high quality down. The Nano-thin treatment vastly improves the down's reaction to water without effecting its weight or loft performance. ULTRA-DRY Down™ retains over 60% more loft and absorbs 30% less moisture when compared with untreated down. Sea to Summit sleeping bags dry out 60% faster than bags with untreated down. The Nano-level treatment also inhibits bacterial and microbial growth, which makes Sea to Summit sleeping bags more hygienic and improves their lifespan.

Responsible Down Standard (RDS): The RDS is helping to shift the entire down and feather industry towards more humane animal rearing and handling practices. Overseen by the industry leading Textile Exchange, the RDS requires independent, third party assessments of all aspects of animal rearing and handling throughout the entire supply chain. By only using down that meets the audited requirements of the RDS we can have confidence that each phase of the collection process has been completed with the welfare and ethical treatment of waterfowl in mind. To find out more about how the RDS is improving animal welfare during down collection, please visit (link will open a new window).


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